Another potential buyer for Maytag has officially come forward. The Newton-based appliance maker reports a preliminary, non-binding proposal from an arm of Chinese appliance maker Haeir, Bain Capital Partners and Blackstone Capitol Partners Four. Under the offer, the group would acquire Maytag for 16-dollars a share, which is two-dollars per share more than what Maytag’s board of directors agreed to last month in a proposal from another investor group, Ripplewood Holdings. Maytag officials say they’re considering the best options for the stockholders.